Without the benefit of their state’s strict new immigration law, officers from a single Arizona county helped deport more than 26,000 immigrants from the U.S. through a federal-local partnership program that has been roundly criticized as fraught with problems.

Statistics obtained by The Associated Press show that the Maricopa County Sheriff’s Office was responsible for deportations or forced departure of 26,146 immigrants since 2007.

That’s about a quarter of the national total of 115,841 sent out of the U.S. by officers in 64 law enforcement agencies deputized to help enforce immigration laws, some since 2006, under the so-called 287(g) program.

The tens of thousands of immigrant arrests show local officials already have a significant amount of authority to enforce immigration laws and help remove illegal immigrants from the country.

But with Maricopa County Sheriff Joe Arpaio the top law officer among all those deputized, questions remain about what’s in store when Arizona gives more officers the power to enforce immigration laws. The federal government already is under fire for doing a poor job of keeping watch on local officers enforcing immigration laws and ensuring safeguards for protecting civil rights are in place.

Arpaio is under federal investigation on allegations of civil rights allegations, which he denies.